Human lens gamma-crystallins: isolation, identification, and characterization of the expressed gene products

Proc Natl Acad Sci U S A. 1987 Sep;84(17):6088-92. doi: 10.1073/pnas.84.17.6088.


We have isolated the individual gamma-crystallins expressed in young human lenses and identified with which of the six known human gamma-crystallin genes they each correspond. We find that at least 90% of the gamma-crystallins synthesized in the young human lens are the products of genes gamma G3 and gamma G4. We demonstrate that gamma G4-crystallin undergoes a temperature-dependent phase separation, and we have measured the low-concentration branch of its coexistence curve (phase separation temperature vs. concentration) up to about 40 mg/ml. By comparison, we found no evidence of gamma G3-crystallin phase separating, even at lower temperatures and higher concentrations. This is consistent with predictions based on sequence homology between human and rat gamma-crystallins. The implications of these findings for human inherited and senile cataracts are considered.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aging / metabolism
  • Amino Acids / analysis
  • Animals
  • Cataract / etiology
  • Cattle
  • Child, Preschool
  • Crystallins / genetics*
  • Crystallins / isolation & purification
  • Humans
  • Infant
  • Multigene Family
  • Rats


  • Amino Acids
  • Crystallins